Control system for refrigerating apparatus



March 20, 1928. 1,662,965

E. S. ENSIGN CONTROL SYSTEM FOR REFRIGERATING APPARATUS Filed March 31;192 6 4 Sheets-Sheet 1 March 20, 1928.

E. s. ENSIGN CONTROL SYSTEM FOR REFRIGERATING APPARA Filed March 31 1926TUS 4 SheetS Sheet 2 fimmy 5 fizmzan/ior .Ziz Sign eezws I March 20, 192E. 5., ENSIGN' CONTROLSYSTEM FOR REFRIGERATING APPARATUS Filed March 51,1926 4 Sheets-Sheet 3 March 20, 1928.

E. s. ENSIGN CONTRCSL SYSTEM FOR REFRIGERATING APPARATUS File M rch 19264 Sheets-Sheet 4 mmmmmmmvmamm W J g 3 N 0000 8 9 a 6 7 \8 m 2%50 M 67 6Z 2 w 8 6 6 5 8 4 M Patented Mar. 20, 1928.

NIT -13;

EMORY S. ENSIGN, OF NEW HAVEN, CONNECTICUT, ASSIGNOR T NATIONALREFRIGER" ATIN G COMPANY, OF NEW HAVEN, CONNECTICU CHUSETTS.

FIE.

CONTROL SYSTEM FOR REFRIGERATING APPARATUS.

Application filed March 31, 1926. Serial No. 98,732.

My invention relates to automatic control of refrigerating apparatus ofthe absorption type in which condensation of refrigerant material andevaporation thereof 6 in the refrigeration department constitutealternating stages of theoperating cycle. 'lhemain object in view is toprovide a system of control which, applied to refrigerating apparatusofthe type designated,

1 and used under conditions which preclude attention and operation bytrained'persons,

will with substantial completeness automatically regulate such apparatusin response to fluctuating conditions either internal or external to theapparatus and maintain it in regularly satisfactory and efficientoperation, in spite of such fluctuations. Domestic refrigerators andsmall commercial apparatus are especially in need of such adequateautomatic control; their requirements for control vary widely Withgeographical situation, with individual demandsfor service. and with thepersonal equation of the user. Control systems involving my inventionmay under some conditions be adequate in relatively simple form and witha minimum of control-factor, while under other conditions they mayrequire supplemental operative factors of organization which affordgreater 0 flexibility and refinement, greater resourcefulness andadaptability to meet and cope with. emergent variables'of environment.

In the drawings hereto annexed, which illustrate a preferred form of myinvention,

Fig. 1 is a diagrammatic representation of the principal factors of arefrigerating apparatus of my preferred form; I

Fig. 2 is a diagram representing a chronometric control for an apparatusof the said 49 type, in its simplest aspect; this represents,

for a basis of demonstration, a type of chronomctric control heretoforesuggested;

Fig. 3 is a diagram, similar in scheme to F ig. 2 representing therudimentary chronomctric control with one factor modified; Fig; 4 isanother diagram, similar in scheme, representing the chronomctriccontrol witha supplemental factor introduced; Fig. 5 .is anotherdiagram, similar in scheme, representing the chronometric co ntrpl withthe characteristics of both Flg. 3' and Fig. 4 included;

of the preferred.

Figs. 11 and 12 are detail 1 elevational views; 7

Fig. 13 is a section on line 1313 of Fig. 6;

Fig. 14 is a section on line l4-14= of Fig. 6; Fig. 15 is a section online 15+15 of Fig.

6; and

Fig. 16 is av diagrammatic representation of the control andrefrigerating apparatus showing electrical connections for the same.

In carrying out my invention as herein shown, I employ as in Fig. 1 agiven mass M of absorbent material in the containerN,

T, A CORPORATION OF MASSA absorbent material to promote reabsorption ofrefrigerant may be a water circulation coil W L represents a floatchamber, and WE a water circulation coil for abstracting heat fromrefrigerant emitted from M and conducted through the pipe P; a two wayvalve V serves to direct water one way or the other from source W; Grepresents a collecting chamber for condensed liquid refrigerantconducted from thefloat chamber through ipe P; B represents a containerfor a re rigerated body, such as brine. F represents a float, and d, dan electric contact or circuit closure, ada ted to function in responsetodepletion o the refrigerant to a predetermined minimum in thecollecting -chamber-G. The factor represented or illustrated by thisfloat and electric'devices will be described in connection. with Figs, 4and 5, and may be ignored in connection with Figs, 2 and 1 For example,assume that the material M is a given quantity of calcium chloride,saturated with ammonia to the condition represented by CeClfiNH, andthat the amount oi ammonia emitted by and reab sorbed in this materialis to be the quantity represented by the change from the stated maximumabsorption to thecondition of the material represented by (laCl lltllVvith the materials taken for example, this range of operation can notbe substantially exceeded without impairing the eificiency of theapparatus.

With these data, with a dependable normal rate of heatinput by theheating charged materiel factor H, it is obvious that, starting with anassumed initial temperature of the fully e given time will elapse, atthe close or" WlllCll substantially all the material will have reachedthe condition. represented by fiefil ri lfi and that, withanlepproprietely designed condenser cooled by e cooling medium (e, g.water, through coil WE} a rate corresponding to the rate and temperatureof emission, the refrigereutainmosia-=-will be cooled be low itsliquefylng temperature at the pres sure produced in the closed system bythe input of heat and thus liquefied, and that this condensedrelrigerant will collect in the chamber Que way of cootrolliiig theduretion of the emission stage eppsretus of this character has heretolore been by the so cumuletioii oi: liqeid refrigerant is the col lectingchamber, in such manner that the input of heat to theabsorbent-generative material she-ll continue {the condenser Operetionalso} until the predetermined maximum quantit r of refrigerant materielhas been emitted from the absorbent-end collected in the collectingchamber If the supply of heat for emission purposes be stesdy andreliable, the time required for emission and collection of refiigerentmaterial is substantially constant; in fact there are sherry situationswhere constant heat-service is not maintained and, ii rate of heat inputfalls substantially, the protrection of the emission stage in asapparatus controlled by liquid-refrigerantlevel willbe such that thetemperature in the chambers served by the apparatus will rise unduly, asfor instance to a degree to permit defrosting or meltifig of the frostedmoisture upon the outer surface of coiitsiiier B,

For reasons and purposes thus indicated, chronometric control has beenproposed as a substitute for control dependent wholly upon selectedlimits of vsiiaht -factors, either obtaining in the refrigerating appsrates or the relrigerated epperatus, or

mosses bothas for instance control by maximum and minimum. of condensedrefrigerant; such external chronometric control, in its simplest aspect,is diagramnmtically illustrated by Fig, 2.

C represents a moving member of any instrument serviceable as aclirononieter. This term, be it understood, is here used in itsetymological sense. The chronometer, in this association may or may notbe regular in its progress throughout the entire cycle in which itmoves; it is essential only that in movement between certain selectedstations in the cycle it shall always normally require the some timeinterval..

The circle O graphically symbolizes the complete cycle. Assume now thatthe material M (Fig. 1) is fully charged with its predetermined maximumcontent of refrigerant material, and that therefore it is in order forthe emission stage of the refrigerative cycle to begin, and that thecontrolling member G of the chronometer, be

ing at or just passing station S, by any means conceivable, be itmechanical, electromechanical, or what one pleases, initiates heatinputto material Ill, and directs a-cooling medium (as by valve V)through the condenser coil NE, and that these conditions will persist inthe apparatus indicated in Fig, 1 until an appropriate factorintervene's to interrupt. lit station R, (Fig, 2) on thecirclerepresentative of the chronometer course or cycle, means areprovided which are'stimulated to action when the controlling memberreaches or is passing the said station, their action, through any trainof operative factors being effective to intei-Tupt beet input to thematerial M, end else to set into operation. means for abstracting heatfrom the said material, to reduce its temperature; This letter will asusual in such apparatus, be accomplished by turning the dew of coolingwater, by way of valve V, from the condenser coil WE and into thecooling coil Will;

With respect especially to the service emciency of the heat source, theemission intervol E, measured by the time required for the chronometriccontrol C to advance from station S to station E is so adjusted (as bydetermining the location on circle 0 of these two stations) that, whenthe heat input is its expected value, the predetermined quantity ofrefrigerant material will have been omitted when the control member Carrives at station E and causes the characteristic reversal of therefrigeration cycle, from emission stage to absorption stage.

It will now be apparent, that if the heat service rote falls belownormal, the time elapsed in progress ofthe control member ijrom stationS to station R will not sufiice tor emission from material M of thenormal quantity of refrigerent, but that al- Eli Xlltl llli though thematerial M has not been exhausted 0 full normal emitted quantity, theemission stage of the cycle will nevertheless be interrupted,arbitrarily so to speak, and reabsorption, with accompanyingrefrigeration, will begin, .and undesirable rise of temperature, such asto cause melting of the accumulated frost on the brine tank '13, willnot be permitted during the heating stage of the cycle. Nevertheless, arigidly predetermined chronometrie control such as is illustrated inFig. 2 can not be expected to remain in phase, so to speak,.with thealternating emission and absorption phases of the refrigeratingapparatus.

A chronometric control of the simple character illustrated by Fig. 2possesses also, and apart from its more fundamental .deficiency, justabove mentioned,.a defect (In the score of economy, in that it providesf )r abstraction of heat as by circulation of water) from the absor entmaterial to begin simultaneously with cessation ofheat-input, and thuswaste energy stored in the material itself and the structure with whichit is associated, as well as raising the temperature of the coolingwater so that high pressure steam is produced for several minutes withresultin objectionable noise in the water pipes. T e control apparatusdiagrammatically illustrated in Fig. 3 comprises provisions foreliminating waste from this cause. Instead of the single station R,equipped with means for abrupt transition from the emission stage to theabsorption stage of the refrigeration cycle, two control stations R andR are provided, station R being equipped with means whereby, when thechronometer control member C reaches or is passing it, the input of heatenergy of the material M is stopped, leaving cooling coil WE inoperation.

After a predetermined interval, when the control member C reaches or ispassing station R means associated with that station, and actuated bythe chronometric control, initiates heat abstraction from the materialM, as b' diverting a stream of water" from of this ei'iodethe material Mis cooled sub .stantial y as much by the evaporation of the emittedrefrigerant' as it would be by the" immediate diversion of cooling waterto the generator. The position of the double or split action reversingstation R, R with relation to the emission stage starting station S willbe determined with reference to the desired normal outputof'ret'rigerant,

intervals, such as illustrated by Figs. 2 and 3, when exactly adjustedto the normal performance of a given refrigerating apparatus and therefrigerator served by it, may prove tolerably reliable and seviceableprovided the conditions under which the whole apparatus is operated. areabsolutely steady. Since,

' however, steadiness both of service load and rate of heat input andabstraction is rather the exception than the rule, and can hardly beexpectcdat all in the performance of domestic refrigeration plants, agreater fiexlbility and adaptability to variant conditions is always tobe desired and often indispens able in the. control lapparatus.

Wide variations in conditions affecting refrigerator service, whetherseasonal or diurnal, internal or ez'zternal, regular or irregular ininterval, require compensation. The

chronometric control apparatus should for i this purpose be subject tocontrol reciprocallyexerted upon it by the refrigeration apparatus.Figures 4 and 5 illustrate diagrammatically the mode in which suchmodification of chronometric control is affected. These two diagrams maybe considered together, since they differ in detail solely'in that Fig.4 shows a single reversal control station R (like Fig. 2)\ whereas Fig;5 SllOWS the double or split control reversal station R R (like Fig. 3).

The time and space factors of the chronometric control are primarilyadjusted so that the period required for progress of'the controlmember'represented by C-from the stage reversal station (R of Fig. 4 orR of Fig. 5) to the stage reversal station S under normal conditionswill terminate in synchrony with the reabsorption of an amount ofrefrigerant equal to that emitted and condensed during the emissioncycle, this representing the predetermined full charge of the collectingchamber G when the refrigerator itself is making its maximum servicedemand. With such an adjustment it is manifest that during periods ofreduced or rinnimum service demand, the chronometricI control memberswould arrive at the reversal station S and initiate the emission stageof the refrigerating cycle before the full charge of refrigerantmaterial previously collected by condensation has been evaporated andreabsorbed. 'lo-atford time for complete evaporation and reabsorptionunder all Service till conditions, some means for interrupting ordelaying the progress of the chronometric control factor during theevaporation and absorption stage of the refrigeration cycle, is to beprovided. This is represented in the diagrams Figs. d and 5 by D, whichI desig-.

hate the detent. The detent might be a physical obstacle, or meansoperated by the chronometric control apparatus itself for interruptingits own driving power, -or what one pleases, provided it be operative topostpone the action of the cycle-reversing instrumentalities associatedwith station S and stimulated to action by the chronoinetricpredetermined extent closes an electric cir-.

cuit cl, and, actuated by itsclosure, the do tent D is withdrawn fromits position in the path of the chronometric control member, and thelatter talres up its interrupted progress and proceeds to station S,there to set in action the train of instrumentalities providedforinitiation of the emission stage of the refrigeration cycle. Thus theabsorption period, indicated by the curved arrow A in Figs. 4: and 5will be longer or shorter, as conditions demand. paratus primarily underthe control of the chronometric apparatus, exerts a secondary reciprocalcontrol on the chronoinetric apparatus, retarding or arresting itsnormal progress to suit variations in. external conditions.

ll n practice the parts will be so adjusted that, even under the extrememaximum of service demand to be expected, the point D will be reached bythe arm C before the liquid ammonia in the chamber G is sufficientlyexhausted to permit the electric closure device cl to operate.

A chronometric control apparatus embodying in full detail one specificexpression of the principles of structure and operation broadlyillustrated in Figs. 1 to 5 inclusive, is shown in Figs. 6 to 15 anddiagrammatically illustrated in relation to the principal factors of therefrigerating apparatus by Fig. 16.

The control apparatus designated generally by the symbol C comprises inits more essential aspects anclectrically actuated chronometcr 12, acontrol member 13 adapted to open and close a switch 14 which controlsthe heater H, also to actuate the valve V in order to change thedirection of liquid fiow vand being further adapted to operate a switch22, thus cutting out the chronometer 'lhe refrigeration ap-' messescircuit in order to permit a secondary con= trol factor to be impressedupon the chronometer by the refrigerating apparatus.

The chronometer 12, the control member member or shaft 13 throughsuitable gearing 15, preferably rotating the latter one revolu- U0?during each complete refrigerating cyc e.

Fixed upon member 13 is the switch actuating element 30 which may beconveniently supplied with substantially radially disposed arms 31,preferablyof fibrous insulating material. Mounted upon an axis parallelto that of shaft 13 is av rotatable disk 35 upon one'face of which aredisposed outstanding parallel pins 36, 37 and 38 which may be suecessively actuated by the respective arms 31 of member 30, therebycausing rotary movement to be imparted to member 35.. A suit able springcontrolled detent 41 is adapted successively to engage adjoining pairsof pins 36-, 37 and 38, whereby member 35 may be intermittently rotatedand retained in successive fixed positions. Upon the other face ofmember 35 is a single outstanding pin 4-2 which is adapted to be engagedwith an irregularly shaped strip 43, in one or the other of the tiredpositions of disk 35, as for example while detent 41 engages pins 37 and38. Strip 4:3 is resiliently held by a spring 39 against an insulatedstop 90, or against the pin 4:2. Pin i2 and the strip together form asnap switch and are adapted to close an.- electric circuit through leads82, 83, 85, and 86 to energizeheater H,

Control member 13 is connected to the aligned shaft 50 of the two wayvalve V which is .illustrated'more specifically in Figs. 10 to 14. Thevalve preferably comprises a hollow block 51 which forms a casing havingthe inlet pipe 52 to permit entrance of the water and having the outletpipes 53 and 54., through one or the other of which the water isalternately permitted to leave the valve.

Fixed upon the end of shaft 50 or integral therewith is a disk 55 whichis shown in Figs. 10 and 12. Block 51 is, provided with a removableannular member 61 forming a bearing for the shaft 50 and having itsintaposed ports 56 which are adapted successively to register with twosegmental grooves 62 upon the adjoining face of member 61 as shaft isrotated. Connected with the intermediate portions of these grooves arelon- Ell 'tudinally disposed conduits 66 in the memr 61 which, in turn,are connected with the passages 63 and 64 registering with theoppositely disposed outlet pipes 53 and 54respectively. A cap 70 isthreaded into block 51 adjoining the other face of disk 55, theseelements forming a suitable chamber 73 connected to the water inlet pipe52. 7 Water may thus pass through ports 56 to one or the. other of thesegmental grooves 62, the corresponding longitudinal conduit 66 andoutlet pipe 53 or 54.

In order to retain disk 55 in comparatively tight engagement with theannular member 61, a suitable coil spring 74 may be inserted in a recessin cap 70 with its end engaging disk 55 to hold that member firmlyagainst block 61, while packing l'l is interposed between cap 70 and theblock 5lfor, a similar purpose. The fact that members and 61 are easilyremovable permits the ready provision and maintainance of a water-tightfit therebetween. Y

It is to be understood that the segmental grooves 62 and ports 56 in thevalve V- are preferably dimensioned and disposed so that just as Waterfiow is ceasing through one outlet it is starting in the other, with theresult that either the absorbent material M or the condenser'is beingcooled. The switch 14 is synchronized with the valve so that there maybea definite period between the opening of the switch and the directing ofthe water flow through pipe 53 to material M, thereby increasing thethermal eficiency of the device or providing a double reversing stationlt R as diagrammatically illustrated in Figs. 3 and 5. I I

Switch mechanism 21, which is designed to permit the regulation of theapparatus by a secondary control factor, comprises a cam disk 20 mountedon member 13 with a notch 26 at one point in its periphery. hd omlng thedisk is disposed a suitable switch 22 comprising a fixed contact 28 anda movable contact 29 at the end of a spring leaf 23 which resilientlyretains a block of insulating material 24 in engagement with the notchedperiphery of cam disk 20. The switch and disk are so arranged inrelation to each other that the block 24 eng"g the periphery of the disknormally hocontact 29 against contact 28, except when the block isengaged in notch 26 at one point in the revolution of the disk, when thecircuit will automatlcally be opened (Fig. 9). Switch 22 is locatedbetween leads 89 and 87 (Flg. 16) and therefore its opening is adaptedto suspend action bf the chronometer, until or unless the switch 12', dwhich is located in parallel with switch 22 is closed.

Referring more particularly to Fig. 16, it may be seen thatthe'chronometer may be energized either through leads 80, 87, 89; and85, when switch 22 is closed, or through leads 80, 81, 88, 89 and 85when switch d (i isclosed. As previously described the last namedswitchis-controlled by the float F, the position of which is determined by thelevel of the refrigerant in collecting chamber G. Ordinarily the controlapparatus will be so designed that switch 22 will be openedapproximately at the time switch 01',

d is being closed under the most severe operating conditions, or, inother words, under practically all working conditions there will be somelapse of time when both of the above described chronometer circuits willbe open.

The typical refrigerating cycle will there-.

parallel parts of its circuit, until subsequent change in the level ofrefrigerant in chamber G opens switch (2 d, permitting the full amountof current to pass through switch22.

It is now evident that T havev provided automatic means whereby thecycles of an apparatus such as a refrigerating device of the absorptiontype may be controlledby achronometer but whereby the action of thatchronometer which is designed to control I fixed parts of the cycle maybe delayed in response to reciprocal regulation afiorded by therefrigerating device to compensate for variations in working conditions,and whereby the apparatus .mayhave a degree of varia le control tocompensate for variant internal or external conditions. It may befurther seen that the direction of flow of the cooling agent such aswater may be automatically controlled in synchrony with the operation ofthe chronometer so that a definite period of time may elapse between theheat input and abstraction of heatprovided for the absorbent material,whereby not only the economy of operation is enhanced, but the coolingeffect of the evaporating refrigerant rather than cooling water servesto-lower the temperature ofthe absorbent material to a point where watermay be diverted through the generator without generation of steam andconsequent undesirable noise. I

I claim:

1. The combination, with absorption refrigeration apparatus of thecharacter designated, of a ehronometric control member,

means arrdnged to be successively stimulat,

ed by the said control member to initiate are absorbent material, meansLo-terminate said heat input, and means to initiate heat abstractionfrom said absorbent material, means adapted to delay progress of saidchronometri'c control member near the close of the absorption stage, andmeans responsive to exhaustion of the condensed r-e'trigerant wherebysaid chronometric control member is made tree to progress normally.

3. The combination, with absorption refrigeration apparatus of thecharacter designated, of a movable chronometric control member, meansarranged to be successlvcly stimulated by said control member toinitiate and terminate in alternate succession the emission andabsorption stages of the cycle of said refrigeration apparatus, andmeans adapted to delay progress of the control member at a portion ofits path corresponding to one part of the cycle, and a second controlfactor adapted to terminate the period or delay, said factor beingactuable by the refrigeration apparatus whereby the period'of delay maybe varied in length in accordance with variant conditions to which thatapparatus is subjected.

4. The subject matter of claim 3- further characterized in that thechronometric control member is operated by energy received through anelectric circuit and in that the means adapted to delay progress of thecon trol member comprises an electric switch 0})? erated by the controlmember at one point of its path to open said circuit, said switchcomprising a fixed contact and a yieldably mounted contact, meansoperated by the control member normally holding the contacts togetherbut permitting their separation at the portion of the cycle during whichthe period of delay occurs.

5. The subject matter of claim 3 further characterized in that thechronometric con trol member is operated by energy received through anelectric circuit, and in that the means adapted to delay. programs oithe control member comprises an electric switch op erated by the controlmember at one point oi. its path to open said circuit, and the memadapted to terminate the period out dolay comprises a second switch in aportion heat to t of the circuit parallel to the first switch, wherebyclosing of'the second switch starts the movement of the chronometer andthe control member, said second named switch comprising a fixed contactand a movable Contact, said movable contact, being connected-to a floatin the refrigerating appara tus, whereby the switch may be closed whenthe level of liquid refrigerant is lowered.

6. The subject matter of claim 3 further characterized in that thechronometer is operated by energy received through an electrio circuitand in that the means adapted to delay progrcssof the control membercomprises an electric switch operated by the con: trol member at onepoint of its ath to open said circuit to permit regulation y a secondarycontrol factor, said secondary control factor being adapted to causeclosing of said electric switch after a period of delay of valriablelength, whereby continued operation of the chronometer through saidswitch and circuit may continue;

7. The subject mater of claim 3 further characterized in that thechronometric control member is operated by energy received through anelectric circuit and in that the means adapted to delay progress of thecontrol-member comprises an electric switch operated by the controlrmember at one point of its path to pen said circuit, and that the meansadapted to terminate the period of delay comprises a second switch in aportion of the circuit parallel to the first switch, whereby closing ofthe second switch starts the movement of the chronometer and the controlmember.

8. The subject matter of claim 3 further characterized in that thechronometer is operable by energy received through an electriocircuit,'said circuit being adapted to be closed when either one of apair of parallel switches is closed, means adapted to hold one switchclosed except at the portion of the path of the control membercorrespondin to the period of delay and means controller? by therefrigerating apparatus to close the other switch at the end of theperiod oi delay to restart the chronometer, said last named means beingadapted to maintain the circuit closed until the first switch isautomatically closed to complete the cycle.

9. The combination, with absorption reirigeration apparatus oi thecharacter designated, ofa chronometric control device, means arranged-tobe successively stimulated by said control device to initiate andterminatc in alternate succession the emission and absorption stages ofthe cycle of said refrigeration apparatus, including means to apply eabsorbent and to abstract heat from the same, whereby refrigerant isemitted'and absorbed, said control device being actuable in response toaclir0nomertic con trol factor, and being rurther actuable in retrolfactor being arranged to provide an in-- terval of delay between saidheat application and abstraction stages, said interval occurring in theportion of the cycle wherein the apparatus is controlled bythe'chronometric control factor, whereby the interValj-is'of a definitepredetermined length.

10. The combination, with absorption refrigeration apparatus of thecharacter designated, of a chronometric control member, means arrangedto be successively stimulated by said control member to initiate andterminate in alternate succession the emission and absorption stages ofthe cycle of said refrigeration apparatus, including means for theapplication of heat to the absorbent and for abstraction of heat from,the same, whereby-refrigerant is emitted and absorbed, saidcontrolapparatus being adapted to provide -aniinte-rval of delay between heatapplicatioli' and; abstraction periods, and means adaptedto. delayprogress of said chronometric control membernear the close of theabsorption stage, and means responsive to the refrigerating apparatuswhereby'the control member may proceed normally after the last namedperiod of delay.

Signed by me at New Haven, Connecticut, this 27th day of March,;1926.

EMORY S. ENSIGN.

